"Given a number n, return the number of positive odd numbers below n, EASY!"

Comparison of null values required . (OP solved it, closing)

RTFM Kata Rule:

Do not modify the ONE_HUNDRED declaration

Read carefully the sample tests, there is more than one bug still in your code.

• did you read the error message you get with the second?
• if so and you don't get it, this is that you don't know yet that || and && are "shortcut" boolean operators.
  • a||b: if a is true, b isn't evaluated (because there is no need) => that's what your missing, here
  • a&&b: if a is false, b isn't evaluated either.